1. Field of Invention
The present invention relates to a low dropout voltage regulator. More particularly, the present invention relates to a low dropout voltage regulator, suitable for use in a hand-held electronic apparatus.
2. Description of Related Art
The hand-held electronic apparatus has been in wide applications, and the battery duration is therefore requested to be longer and longer. If the power consumption due to quiescent current in the whole system can be reduced, the operation duration for the hand-held electronic apparatus in use can be prolonged. However, for the usual low dropout voltage regulator, the quiescent current does not vary with the loading current.
For example, FIG. 1 is a drawing, schematically illustrating the conventional low dropout voltage regulator 100. In FIG. 1, the low dropout voltage regulator 100 receives a reference voltage VREF, and provides an output voltage Vout. Since the current consumed by the buffer 101 is almost constant, the consumption due to the quiescent current is still greater than at a certain level even if the whole circuit is at a low loading condition, that is, the loading current on the resistor RL being small. This continuous power consumption would decrease the operation duration of the hand-held apparatus.